For some, it's a day of celebration, for others it's about sorrow and mourning. SBS News looks at how Australia got to this point in the debate and where things could go next.
Australia Day - or Invasion Day - will be marked around the country on Sunday in dramatically different ways.
Some Australians will celebrate with barbecues and enjoy fireworks displays, while others will look back at our history and mourn.
So what is the story behind this increasingly contested national day?
Each year, Australia Day falls on 26 January.
It's not the date the First Fleet landed in Australia, as many think.
The men of the First Fleet set ashore at Sydney's Botany Bay a whole week before. On finding it unsuitable, they relocated further north.
Instead, it's when a flag was raised.
Material from the National Australia Day Council explains the significance.
"Captain Arthur Phillip, commander of the First Fleet of eleven convict ships from Great Britain, and the first Governor of New South Wales arrived at Sydney Cove on January 26 and raised the Union Jack to signal the beginning of the colony," it says.
Australia Day over the years
Frank Bongiorno, head of the Australian National University's School of History, said Australia Day in its current form is actually quite new.
"The 26th of January has been commemorated and celebrated, marked in one way or another since the early days of the colony," he told SBS News.
But, he said for many years, "it was very much a Sydney event, it was very much about NSW".
Sydneysiders celebrated the date as First Landing Day or Foundation Day with drinking and regattas.
For 200 years, the other states commemorated their Australian-ness on Regatta Day (Tasmania), Proclamation Day (South Australia), Empire Day, and several other days.
"And as late as the 1960s, there was absolutely nothing in Canberra [on January 26], for instance ... It wasn’t marked in any way there," Professor Bongiorno said.
In fact, the 26 January public holiday was only declared in 1994.
Today, the Australia Day Council says "more than half of all Australians participate in Australia Day, attending events organised by state governments, local councils, community groups or getting together with family and friends".
In addition, more than 27,000 new Australians will become citizens on Australia Day at ceremonies around the country.
A day of mourning
Australia's Indigenous people were living on the continent for more than 60,000 years before the arrival of the British.
So to many Indigenous and non-Indigenous people, the date has a very different meaning.
"The date has long been a difficult symbol for many Aboriginal and Torres Strait Islander people who see it as a day of sorrow and mourning," material from the National Australia Day Council says.
Since 26 January, 1788, Indigenous people have endured oppression and dispossession on a wide scale.
According to Australians for Native Title and Reconciliation (ANTaR), "there was armed conflict, commencing years of frontier conflict, massacres, forcibly stealing other First Nations' land, moving them off it, stealing vital food resources, and smashing the way of life that had been lived for thousands of years".
"The uninvited British arrival and encampment in Sydney Cove January 26, 1788, was both a staging post, and the start, of a long invasion of First People's land."
For many years, there has been resistance to celebrating 26 January.
Mr Bongiorno said, "Aboriginal groups announced a day of mourning back in 1938 ... So there's nothing new about the date being argued over and contested".
He said the idea of protest reached the mainstream on Australia Day 1988, the country's bicentennial year.
"We had probably two million people sitting around Sydney Harbour watching the tall ships, the First Fleet re-enactment with Prince Charles and Princess Diana and Bob Hawke."
"But we also had ... about 40,000 Aboriginal people and others sympathising with their cause marching in Sydney on that day as well."
"We had these two stories about the Australian past and perhaps also about the Australian present being enacted on that one day."
As a result, some refer to 26 January as "Invasion Day" or "Survival Day".
Since 1988, the controversy around the date has only grown.
Mr Bongiorno said recent decades have seen a further "change in our historical consciousness".
"There's an understanding that there is a history of Australia that isn't just about hardy pioneers and peaceful settlement of this country. It's about violence and dispossession. It's about mourning."
And many individuals and organisations have acted on this, with the "Change the Date" movement gaining momentum.
In 2017, Melbourne's Darebin and Yarra councils decided to scrap their Australia Day citizenship ceremonies and celebrations.
Then-prime minister Malcolm Turnbull said the decisions were an "attack on Australia Day" and both councils were stripped of their right to hold citizenship ceremonies.
Other councils including Moreland in Victoria, Byron Bay in NSW, Fremantle in Western Australia and Launceston and Flinders Island in Tasmania have also curbed their Australia Day activities.
In November, the Inner West Council announced it would be the first in Sydney to "move all celebratory events away from January 26".
"Attitudes towards 26 January are changing in the community," Inner West Mayor Darcy Byrne said.
"For Aboriginal people, the date represents the beginning of colonisation, dispossession, the removal of children and deliberate destruction of language and culture. A growing number of Australians want that to be respectfully acknowledged."
For now, the Greens are the only major political party calling for a change of date for Australia Day.
Professor Bongiorno said these developments "speak to a large, important, powerful shift in the way Australians understand their past".
"It can't simply be seen as a straightforward tale of celebration. There is much more to it than that. It is fundamentally a contested past."
What does the government say?
Prime Minister Scott Morrison is a staunch supporter for keeping Australia Day on 26 January.
In last year's Australia Day message, Mr Morrison offered insight into why he views the date as significant.
"We're a country made up of so many peoples. Our Indigenous peoples, settlers, migrants who have come from all around the world to make us the amazing country that we are today," he said.
"We celebrate all Australians, all their stories, all their journeys. Australia Day is the day we must come together. It's on this day, January 26, because that is the day that Australia did change forever and our modern nation began."
Last year, the government announced it would mandate that local councils had to hold citizenship ceremonies on Australia Day.
"If a council doesn't hold ceremonies on Australia Day, then they lose the right to hold them and the government would hold them directly," Immigration Minister David Coleman said at the time.
And as recently as last week, Mr Morrison slapped down any debate around changing the date.
"It's not even a debate we're having at the moment. I don't want to be distracted by that," he told Seven's Sunrise.
The significance of January 25
In a recent interview with SBS News, Sydney Festival director Wesley Enoch, who is Indigenous, said current debate around Australia Day should push people to think far deeper about our national identity.
"The 26th of January just doesn't have enough meaning. So change the date, don't change the date, that's another argument. Let's actually see who we are as Australians [first]," he said.
"In Israel, before their national day ... they have a Holocaust Remembrance Day, and I think we should do something similar, when we say OK, on the 25th of January let's remember the day before it all changed."
He said Australians could consider "what did First Nations Australians think and feel on that day? Let's remember that, then we can remember the arrival of the boats … But let's remember it in context".
"The more meaningful we can make our reflection on our national day, then we'll know where to put it," he said.
"Should it be on the 26th of January? Maybe, but let's ask the questions first - what does it mean to have a national day? And what does it mean to be Australian?"